Rasp unit



Dec 26, 1950 P. c. NElLsEN 2,535,088

RAsP UNIT Filed Aug. 8, 1947 2 Sheets-Sheet 1 Patented Dec, 26, 1950 UNITED STATES PATENT OFFICE RASP UNIT Peter C. Neilsen, Chicago, Ill.

Application August 8, 1947, Serial No. 767,587

1 Claim.

The present invention relates to tire rasps and particularly to a toothed element for a tire rasp and the method of making same. The invention is particularly applicable to a drum type of rasp wherein a perforated steel band or perforated teeth holders are mounted on a drum or Wheel. This Wheel in turn is mounted on a shaft or arbor for rotation and a plurality of sharp teeth project outwardly from the peripheral face of the thus banded wheel. As the Wheel is rotated at a relatively high velocity the moving teeth form an effective abrading surface against which a rubber tire may be applied for preparing the tire surface for vulcanizing or recapping.

An object of the invention is to provide a relatively inexpensive toothed element for use on such a rasp and one that can be easily and simply replaced. It is further intended to provide such an element that is effective and efficient in performing its intended bufting action and one that has a relatively long life compared with conventional rasp teeth.

Further and other objects of the present in.- vention will become apparent from the following description and from the drawings, in which Fig. 1 is a side elevational view of a completely assembled rasp embodying the present invention;

Fig. 2 is a vertical sectional view through the rasp taken on the line 2-2 of Fig. 1;

Fig. 3 is a fragmentary plan 'view of the peripheral band that holds the toothedelements on the drum; .v

Fig. 4 is an enlargedperspective view of one of the toothed elements;

Fig. 5 is a side elevational view of a-coil of metal stripping from which the toothed elements are manufactured;

Fig. 6 is an enlarged, fragmentary, perspective view of a strip of metal that is shown in coil form in Fig. 5;

Fig. '7 is a transverse sectional view through the strip of metal taken along the line 1 1 of Fig. 6;

Fig. 8 is a plan view of part of the strip of metal shown in Fig. 5 but showing a toothed element formed from this strip;

Fig. 9 is an elevational view of the toothed element and strip shown in Fig. 8;

Fig. 10 is an elevational view of the toothed element illustrated in Figs. 8 and 9; and

Fig. 1l is a transverse sectional view taken through one of the teeth, the view being taken on the line II-II of Fig. 10.

For purposes of illustration a single embodiment of the present invention is shown and de- 56 scribed herein. It is recognized, of course, that numerous modications can be made in this specific embodiment without departing from the intended scope of the invention.

Referring to the drawings and particularly to Figs. 1 to 3 inclusive, the invention is illustrated in conjunction with a rasp generally indicated at I5 that includes a drum made up of a pair of web faces I6 that are provided with peripheral flanges I'I on which is supported an annular band generally indicated at I8. The assembly is mounted on a shaft or arbor I9 that is threaded at one end as at 20 to receive one or more nuts 2 I.

The band I8 comprises an annular cushion element 22 about which is mounted an annular backing sheet 23. A perforated tooth element holding member 24 is mounted circumferentially about the backing sheet 23 and as shown in Fig. 3 this holding member 24 is perforated throughout its area as indicated at 25, the perforations being arranged in horizontal alignment extending transversely across the holding member. A toothed element 25 in the form of a relative flat plate-like member 21 is provided along its marginal side edges with a plurality of teeth 28 that all extend in the same direction substantially at right angles to the `plane of the plate-like member 2'I. These toothed members 26 are adapted to be held' by the holding member 24 with the plate-like portion 21 resting against the underneath face of the holding member 24 and the teeth projecting through the apertures 25 in the holding member 24.

Referring now to Figs. 4 and 8 to 10 inclusive the teeth 28 of the toothed elements 2B are each provided with a chisel or cutting edge 29 that faces outwardly in a lateral direction along the outer vertical edge of each tooth. The inner face 3l! of each tooth is relatively blunt. As shown in Fig. 9 each tooth is slightly curved from top to bottom toward one end of the tooth element 26 and as shown in Fig. 10 the teeth on both sides `of the toothed element toe outwardly and are sharpened to a relatively sharp point. As shown in Figs. 4, 8 and 9 the teeth'are spaced substantially at equal distances along both edges of the toothed element 26 and the teeth along one edge are out of alignment with respect to the teeth along the other edge of the toothed element so that in eiect the teeth on both edges are staggered.

Referring to Fig. 1 let it be assumed that the rasp I5 is rotated in a clockwise direction on the shaft or arbor I9. OneIof the toothed elements 26 is designated by the reference character 26 in Fig. 1 and in this toothed element the row of teeth indicated at 28a would include the leading teeth since the rasp is rotating in a clockwise direction, whereas the row of teeth 23h would include the following teeth. The leading edge of each of the leading teeth in row 28a is the chisel or sharp edge 29 illustrated in Fig. 10, whereas the opposite edge 3B of each of the teeth 28a constitutes the blunt edge illustrated in Fig. 11. Each of Ithe teeth iin-row 28h has 'its sharp -ror chisel edge disposed on the rear side'cwith respect to the direction of rotation of the rasp I5.

In its operation the rasp I5 is rotated and an automobile tire casing or the like to be vulcanized or recapped is brought into engagement with the rotating teeth on the raspI'S. iikrvery i effective buing action is produced .due to l.the sharpness of the teeth, their relative curvatures,

and the provision of chisel edges along the 'leading edges of the alternate rows of teeth.

`-Sincethe chisel edges of the teeth-arranged--in fthe alternate rows `28h are disposedcon the :rea-r ysides of the teeth' with :respect -to the-direction of rotation of the Yrasp I5, .an vabrading yaction Vrtakes-:place::between 'these teeth andi-the .emery :contents in the rubber'fof the tire casing being bu'ffedwhich provides avery effectivefsharpening 'action along these ychisel edges-'of ythel teeth. Thus whilepthe .rows 'of' teeth corresponding to TOWv 28a areV cutting intothe :rubber to provide Y :the buing` action, the .next rowsnof teethb tendp to vutilize, their lfjorwardblunt edges'tdae'- move or--scrape faway rubber that is` cut by'ithe forward teethy 28a'l while-:at: the same time the -chisel Vedges of the teeth in lrowswoor-responding i1'- *of the teethand permits 1a 'given rset of'toothed elementsfZ'to be'used over 'and over againon a vvconsiderable number-of tires.

'.Thefreplacementzofwvorn o ut pr brokenitoothed elements canhe :simply-accomplished by merely 'disassembling the rasp SI15 :by arst removing rmt 1or nuts 2:I Aand `withdrawingYthe :raspelements from the arbor I9. This allows `for separation fofthe'various elements making up .theiraspband ltsozthat the wornou'tior'broken toothedxelement z-2E-may he k'removed and replaced vwith fa new The toothed element Ziafmaybe manufactured inavver-yfsimplemanner. Ametal strip 1H 'from a l'oll 31a may be fedthrough :a -|nfxachine that.

bevels the side-edges as indicated .ati32`in Figs. $6 'andl k'7. This bevelingshouldzbe iaccomplished'to provide a sharp chisel edge 32a which as will become apparent provides the chisel edges 29 of the teeth that are to be formed. This beveled edge can either be formed by rolling or grinding or the like or the edges may be molded into shape to produce the chisel or knife like edge 32a.

The strip is next fed into a punch or a similar device that cuts and bends the teeth 28 to the position shown in Figs. 8 to 10 inclusive. The 'toothed' elements thus formed are 'then cut off from thecon'tinuous strip 3| and thenthe element is ready for use in the rasp I5.

As previously mentioned the teeth are disposed Viwith their points hooked outwardly away from the longitudinal center line of the toothed element. This allows the leading teeth on each toothed elementto feed or dig into the surface of the tire that is applied to the rasp during the buing operation.

I claim:

AJrasp unit 1comprising.astrip--of steel having .a plurality v,of elongated, ,.sharp pointed y :cutting and Yabrading `:prongs projectingaupwardly therefrom Yand spaced.- along. opposite longitudinal edges thereof, lthe fprongswalong `one :edge being staggered with respect: to -the l.prongs :along the 4.other edgeyeachfprong.onfeaehzside ofthe strip havinga sshaxpicutting :edge which-extends along the. Afull 4length thereof.,- the.A cutting edges of the Iprongs -a-long oneedge"-ofy thel strip being oppor sitely-facing:withl respectf tothe cutting edges ofithe` prongs :along :the other: edge of. "the strip, -eachfacing foutwardly of fthe 'strip iin a direction transversely ofrtlrelcngth thereof, :the side face of each:prong opposite said'cutting :edges being .ffiatiandpositiuned' inwardly fofy .said strip, vsaid euttingsedge :of aeach :prong-.lying :along the outer :edge pf strip, -each :pronglbeing fcurved in a direction outwardly ofthe/strip, `whereby :as the `striprfis.movedtransversely ofiits :length in aicutting operation; 'the .prongs .positioned :along .the leading edge of the strip present/their'cutting -e'dgestoitheV wvork'zand lean into vit to =cut, and the @prongs :along .the .following Ae dge of :the strip Apresent their 'iilat'facesgito .the work :and lean Iaway ffroxnrit. .'soffthat Ythe .trailing "cutting edges 4are buffedbyit.

TEIER C. INEILSEN.

:BIEEEBENGES 'CITED The'ollowingreferences are-of recordin-the -file of this patent:

UNITED sTA'rEsrArENTs 

